Question

我有通过UI删除和编辑核心数据实体的功能。尽管更改在UI中有效，但在返回视图时不会保留这些更改。我相信我已经错过了一些不会导致任何豁免的事情，但是无法弄明白。是否只是在删除函数的末尾添加标准的save throw和catch？除非是这样才能解开错误？要么！使用

我已将函数的开关案例包括在内：

func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {
    switch (type) {
    case .insert:
        if let indexPath = newIndexPath {
            workoutDesignerTable.insertRows(at: [indexPath], with: .fade)
        }
        break;
    case .delete:
        if let indexPath = indexPath {
            workoutDesignerTable.deleteRows(at: [indexPath], with: .fade)
        }
        break;
    case .update:
        if let indexPath = indexPath, let cell = workoutDesignerTable.cellForRow(at: indexPath) as? RoutineTableViewCell {
            configure(cell, at: indexPath)
        }
        break;
    default:
        print("...")
    }
}

删除功能

   func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == .delete {
        // Fetch Exercise
        let UserExercise = fetchedResultsController.object(at: indexPath)
        // Delete Exercise
        UserExercise.managedObjectContext?.delete(UserExercise)
    }
}

Answer 1

我认为你需要这样的东西

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == .delete {
        let UserExercise = fetchedResultsController.managedObjectContext
        UserExercise.delete(fetchedResultsController.object(at: indexPath))
        do {
                try UserExercise.save()
        } catch {
        // Replace this implementation with code to handle the error appropriately.
        // fatalError() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
        let nserror = error as NSError
                    fatalError("Unresolved error \(nserror), \(nserror.userInfo)")
        }
    }
}

在对实体进行更改时，核心数据的问题仍然存在

1 个答案: